Mechanical door interlock system

ABSTRACT

A mechanical door interlock system having a mechanical locking section used to prevent the opening of one door to a chamber or the like if an opposing door is not closed. The opening motion of one door allows a cam plate, under tension, to rotate and move a connecting rod. The motion of this rod prevents the rotation of the locking section of the other door, with the effect of locking this door.

United States Patent 1191 111 3,826,520 Ross et al. July 30, 1974 MECHANICAL DOOR INTERLOCK 1,840,819 1/1932 Pierce...... 70/262 SYSTEM 2,926,012 2/1960 Moher 49/68 3,174,193 3/1965 Smith 49/68 Inventors: Gerald Ross, Des Flames; 3,602,536 8/1971 Gamble 292/127 Douglas E. Cromwell, St. Charles, both of 111. P E R b L w If rima xaminer- 0 ert o e [73] Assrgnee: The United States of America as z Agent, or Firm Harry Herbert, In;

represented by the Secretary of the cab N Erlich Air Force, Washington, DC.

[22] Filed: Mar. 21, 1973 g [21] Appl. No.: 343,315 S RACT A mechanical door interlock system having a mechan- [52] US. Cl 292/30, 292/53, 70/262, ical locking Section used to prevent the opening of one 49/68 door to a chamber or the like if an opposing door is [511 CIM E051) 53/00, E051) 63/14 E059 19/10 not closed. The opening motion of one door allows a [58] Field of Search 292/33, 30, 53, DIG. 3;. cam plate under tension, to rotate and move a 70/262, 263, 265, DIG. 65; 49/68 necting rod. The motion of this rod prevents the rotation of the locking section of the other door, with the [56] References cued effect of locking this door.

UNITED STATES PATENTS 1,685,998 l0/1928 Hagstrom 292/18 8 Claims, 3 Drawing Figures 44; 6 4e 1 (ll 3' PAIENTED 1113 0 1974 sum 1 or 2 TMFU H BACKGROUND THE INVENTION This invention relates generally to a door interlock system, and more particularly, to a mechanically operated interlock system which controls the operation of the access doors enclosing the ends of an air lock compartment.

There are many instances when it is necessary to provide a door interlock system in which it is impossible to unlock one door of a compartment unless the other door is locked. For example pressure or vacuum vessels, containment vessels, pressure tunnel entrances, high altitude test chambers, submarines, astronautical vessels and other vessels where it is necessary to provide convenient access for personnel and equipment without disturbing the fluid-tight integrity of the vessel are some of the system which would incorporate a door interlock. Another such system is an air lock which normally comprises an intermediate fluid-tight compartment interconnecting the interior of an enclosed vessel with the exterior of the vessel. Access to the air lock compartment is provided by doors at either end thereof. To facilitate the use of the air lock, doors of the quick opening" type are generally used. In order to preserve the fluid-tight integrity of the vessel penetrated by the air lock, the door system should be equipped with an interlocking system which prevents both doors from being opened at the same time.

I-leretofore, this interlocking system was of a complex construction and in many instances utilized electric power sources for its operation. These proved to be highly unreliable, not only because of mechanical failure, but also because of electrical power supply failure, both of which could cause inoperation of the interlock system.

SUMMARY OF THE INVENTION The instant invention overcomes the problems set forth hereinabove and is a purely mechanical door interlock system which provides a fast, positive acting and foolproof locking and interlocking construction. The interlock system described hereinbelow is sufficiently simple and light weight that it may be operated with a minimum of effort and without reliance on external power sources. The opening motion of one door of the instant invention allows for the rotation of a cam plate under the tension of a spring thereby allowing for the movement of a connecting rod attached thereto. The motion of this connecting rod prevents the rotation of the latch of a second door and thereby prevents its accidental unlocking.

Construction of the locking arrangement of both doors is identical in nature and therefore facilitate its manufacture. The simple sliding connecting rod provides the only communication between latches and is capable of automatic reset when both doors are closed.

It is therefore an object of this invention to provide a door interlock system which relies solely on its mechanical construction for its operation.

It is a further object of this invention to provide a mechanical door interlock system which utilizes identical latch assembliesfor the interlocking system of each door.

It is a further object of this invention to provide a mechanical door interlock system which is economical to produce, highly reliable in operation and which utilizes conventional currently available components that lend themselves to standard mass producing manufacturing techniques.

For a better understanding of the present invention together with other and further objects thereof reference is made to the following description taken in conjunction with the accompanying drawing and its scope will be pointed out in the appended claims.

DESCRIPTION OF THE DRAWING FIG. 1 is a fragmental plan view of the mechanical door interlock system of this invention shown partly in cross section;

FIG. 2 is an enlarged side elevational view of the ball and pin arrangement utilized in the locking mechanism of the mechanical door interlock system of this invention and shown partly in cross section; and

FIG. 3 is a side elevational view of a portion of the mechanical door interlock system of this invention shown partly in cross section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to FIG. 1 of the drawing which shows a plan view of the mechanical door interlock system 10 of this invention. This interlock system 10 is interposed between two adjoining doors 12A and 128 located at the entrance and exit ends, respectively, of any pressure vessel or the like such as an air lock (not shown). The door interlock system 10, to be described hereinbelow in detail, is made of two identical mechanical locking sections 14 and 14, each section being operatively connected with doors 12A and 128 respectively. The reference numerals utilized in describing identical elements of sections 14 and 14' will be identical except for a prime inserted after each numeral associated with section 14. Furthermore, in describing the instant invention only one such section 14 will be described in extreme detail, while the other section 14 will be referred to in broad terminology.

Mechanical locking sections 14 and 14 are interconnected by a control rod 16 which is shown in a broken configuration in FIG. 1. A locking compartment or housing 18 encloses a multi-layered cam assembly 20 which is illustrated in more detail in FIGS. 2 and 3 of the drawing. A door release 22 which is secured to compartment 18 by any suitable securing means such as safety chain 23 is operatively connected to cam assembly 20 by means of a ball and pin arrangement 24 shown in detail in FIG. 2 of the drawing.

Reference is now made to FIGS. 1 and 3 in conjunction with a detailed explanation of the locking section 14 of door interlock system 10 of this invention. Multilayered arrangement 20 is made up of a plurality of cam plates 30, 32 and 34 fixedly secured together on rod 26 and rotatably mounted within compartment 18 by rod 26 and spacer members 28. A second spacer member 36 is utilized to rigidly secure outer plates 30 and 34 at a predetermined distance from each other. A pair of upstanding elements 38 and 40 are rigidly secured to or integral with plates 30 and 34. Any suitable biasing means such as a pair of extension springs 41 and 42 are secured at one end thereof to upstanding elements 38 and 40, respectively, and at the other end to a pair of elements 44 respectively, each of which are fixedly secured to the inner sections of compartment 18.

The ball and pin arrangement 24, best shown in FIGS. 1 and 2 of the drawing, is utilized in conjunction with door lock release 22 in order to rotate the multilayered c'am assembly in the manner to be explained hereinbelow. Door release 22 has a rod 46 which is secured by any suitable locking means such as pin 48 to ball and pin arrangement 24. Ball and pin arrangement 24 is comprised of a bearing member 50 interposed between plates 30 and 34 and held in position by balls 52. Balls 52 are located within cutout portions 54 within bearing member 50 and apertures 56 in plates 30 and 34. Arrangement 24' thereby rotatably secures door release 22 to cam assembly 20 in order to allow for the rotation of multi-layered cam assembly 20 upon the insertion or withdrawal of release lock 22.

Again referring to locking section 14, and more particularly to multi-layered cam assembly 24, middle cam plate 32 has a curved portion 60 thereon which engages the outer ends 62 and 64 of control rod 16 when locking section 14 is in the unlocked position. In the position shown in FIG. 1 of the drawing with door 12A in the unlocked position and door 12B in the locked position one end 62 of'control rod 16 bears against portion 60 thereby preventing the withdrawal of the other end 64 of control rod 16 to a position against portion 60. Thus, cam assembly 20' cannot rotate and door 123 remains locked until door 12A is locked. The move ment of control rod 16 is regulated by the position of cam portions 60 and 60 as well as by any-suitable biasing means such as spring 66 best shown in FIG. 3 of the drawing.

Upon the insertion of door release 22 and subsequent movement of control rod 16 to the position shown in FIG. 1, spring 42 assists in the rotation of the multilayered cam assembly 20 to the position shown in the drawing wherein extension 40 is now drawn inwardly allowing for the opening of door 12A. With the cam assembly 20 in this position curved portion 60 of plate 32 rides against the end 62 of control rod 16.so as to prevent the movement of end 64 of control rod 16, thereby preventing the rotation of the other cam assembly 20'. It is thereby seen that only one door 12A or 128 may be opened at one time. lf it then becomes necessary to open the other door 128 the closing of door 12Arotates the cam assembly 20 in the counterclockwise direction against the action of spring 42 pushing out door release 22 and allows for the movement of control rod 16 in a direction toward locking section 14 so as to release and allow for'the rotation of the other cam assembly 20'. i

; MODE OF OPERATION Reference is now made to FIG. 1 of the drawing. When both doors 12A and 12B are in the locked position (not shown) and it becomes desirable to unlock one of the doors (for example door 12A), it is only necessary to insert door release 22 to the position shown in FIG. 1. This action causes the'clockwise rotation of cam assembly 20. With cam assembly 20 in this position end 62 of control 'rod 16 rests against curved portion 60 of middle cam plate 32.

impossible to open door 128 since door release 22 is prevented from being inserted by the immovable control rod 16. Door release 22 cannot be inserted until door 12A is closed and the subsequent counterclockwise rotation of cam assembly 20 takes place. This rotation of cam assembly 20 removes curved portion 60 of middle plate 32 from blocking the movement of control rod 16, thereby allowing the insertion of door release 22' to take place. Furthermore, door 12A can be reopened in the manner set forth hereinabove at any time that door 128 is not open. The above procedure of the door interlock system of this invention is not only highly reliable but also simple in operation.

Although this invention has been described with reference to a particular embodiment it will be understood to those skilled in the art that this invention is also capable of a variety of alternate embodiments within the spirit and scope of the appended claims.

We claim:

1. A' mechanical door interlock system comprising a first door, a first locking section operably connected to said first door, a second door, a second locking section operably connected to said second door and means interposed between said pair of locking sections for controlling the action of said locking sections; each of said locking sections having cam means rotatably mounted therein for engaging said control means, a door release operably connected to said cam means for movement therewith and a plate rotatably mounted within said locking section, said plate having an upstanding element thereon for engaging one of said doors, whereby when one of said doors is in the open position, said cam means associated with the lockingsection of the other door is prevented from rotating by the action of said control means thereby preventing the opening of said other door.

2. A mechanical door interlock system as defined in claim 1 wherein said plate is fixedly mounted to said cam means and rotatably mounted within said locking section.

3. A mechanical door interlock system as defined in claim 2 wherein said door release is secured to said cam means by a ball and pin arrangement and is capable of rotating said cam means only when said control means allows rotation of said cam means to take place.

4. A mechanical door interlock system as defined in claim 3 wherein means is secured to said upstanding element for biasing said upstanding element out of engagement with said door.

5. A mechanical door interlock system as defined in claim 4 wherein said control means is spring biased against at least one of said cam means.

6. A mechanical door interlock system as defined in claim 5 wherein said control means is in the form of a rod.

7. A mechanical door interlock system as defined in claim 6 wherein each of said locking sections has another plate rotatably mounted thereon and said cam means is sandwiched between said pair of plates.

8. A mechanical door interlock system as defined in claim 7 wherein said ball and pin arrangement is movably mounted between said pair of plates. 

1. A mechanical door interlock system comprising a first door, a first locking section operably connected to said first door, a second door, a second locking section operably connected to said second door and Means interposed between said pair of locking sections for controlling the action of said locking sections; each of said locking sections having cam means rotatably mounted therein for engaging said control means, a door release operably connected to said cam means for movement therewith and a plate rotatably mounted within said locking section, said plate having an upstanding element thereon for engaging one of said doors, whereby when one of said doors is in the open position, said cam means associated with the locking section of the other door is prevented from rotating by the action of said control means thereby preventing the opening of said other door.
 2. A mechanical door interlock system as defined in claim 1 wherein said plate is fixedly mounted to said cam means and rotatably mounted within said locking section.
 3. A mechanical door interlock system as defined in claim 2 wherein said door release is secured to said cam means by a ball and pin arrangement and is capable of rotating said cam means only when said control means allows rotation of said cam means to take place.
 4. A mechanical door interlock system as defined in claim 3 wherein means is secured to said upstanding element for biasing said upstanding element out of engagement with said door.
 5. A mechanical door interlock system as defined in claim 4 wherein said control means is spring biased against at least one of said cam means.
 6. A mechanical door interlock system as defined in claim 5 wherein said control means is in the form of a rod.
 7. A mechanical door interlock system as defined in claim 6 wherein each of said locking sections has another plate rotatably mounted thereon and said cam means is sandwiched between said pair of plates.
 8. A mechanical door interlock system as defined in claim 7 wherein said ball and pin arrangement is movably mounted between said pair of plates. 